The present invention relates to dishwashing appliances and, more particularly, to a wash liquid spray system within the appliance.
U.S. Pat. No. 3,951,683 to Jarvis et al, assigned to the assignee of the present invention, discloses a vertically extending hollow tower attached to a lower dish-supporting rack. A rotatable spray arm is mounted on the upper end of the tower so that wash liquid spray ejected therefrom causes the arm to rotate. A bellows-like coupling, coupled to a lower spray arm, is provided directly beneath the tower when the lower dish-supporting rack is in its operating position. As wash liquid is forced upwardly through the bellows-like coupling member, it expands and contacts the lower end of the tower to provide a seal. Wash liquid flows from the pump through the tower and to the upper spray arm for distribution onto the dishes within the washing chamber of the appliance. An upper dish-supporting rack is positioned above the upper spray arm so that the wash liquid is distributed onto dishes within the upper and lower dish-supporting racks. The height of the tower and the upper spray arm is fixed with respect to the lower and upper dish-supporting racks.
There are instances when it is desirable to have the upper spray arm closer to the upper dish-supporting rack than that provided by the fixed height tower of Jarvis, et al. For example, if the height of the tower were adjustable, larger pans and dishes could be contained within the lower dish-supporting rack. However, there are also instances when it is more desirable to have the spray arm at the height provided by Jarvis, et al. It is particularily desirable for the vertical position of the spray arm to be adjustable where the vertical height of the upper dish rack may be selectively adjusted with respect to the lower dish rack. In this case the adjustability of the spray arms position allows a proper relationship to be maintained between the spray arm and the upper dish rack.
Considering the drawback of the tower having a fixed height with respect to the upper and lower dish-supporting racks, we have developed a tower which selectively retains the upper rotatable spray arm at a lower or an upper level. The height of the upper spray arm is easily ajustable by the operator and improves the overall operation of the appliance.
During the preparation of this application, the following additional patents were considered:
U.S. Pat. No. 1,577,225 to Granger;
U.S. Pat. No. 2,726,666 to Oxford;
U.S. Pat. No. 3,077,200 to Guth;
U.S. Pat. No. 3,404,841 to Brittain et al;
U.S. Pat. No. 3,598,130 to Nolte et al;
U.S. Pat. No. 3,813,043 to Mordehai;
U.S. Pat. No. 3,951,684 to LaPrad et al;